CN1036011C - Spherical catalyst component for olefin polymerization, preparation method and application, and spherical catalyst - Google Patents

Abstract

A spherical catalyst for α-olefin polymerization, which is composed of halo-titanium compound carried on a magnesium chloride alcoholate carrier, characterized in that the carrier is directly synthesized from alcohol and magnesium chloride in silicone oil, white oil medium magnesium chloride alcoholate spherical carrier , start to react with halo-titanium compound at -20°C, in the presence of organic acid polyester, raise the reaction temperature to 110-130°C, and the characteristics of the catalyst are as follows: The X-ray spectrum of the catalyst appears at 2θ at an angle of 15° Diffraction peak, there is no diffraction peak at 2θ of 35°, but is replaced by the "halo" of maximum intensity from 28 to 36°; this catalyst is suitable for homogeneous α-olefins, such as ethylene, propylene, butene-1, etc. The polymerization reaction and the copolymerization reaction of their mixture can obtain a spherical polymer with a particle diameter of 1-5 mm.

Description

Spherical catalyst component for olefin polymerization, preparation method and application, and spherical catalyst

The present invention relates to a spherical catalyst component for olefin polymerization, a preparation method and application, and a spherical catalyst prepared from the component.

Conventional catalysts for olefin polymerization originated in the 1950s, but due to their low activity, the polyolefin production process is complicated. At the end of the 1960s, there was a patent on tetravalent titanium compounds supported by magnesium compounds as olefin polymerization catalysts. Since the utilization rate of the titanium atom active center is improved by using the carrier, the catalyst activity is much higher than that of conventional catalysts. For polymerization catalysts of α-olefins with 3 or more carbon atoms, in order to ensure the stereoregularity of the polymer, some electron donors are often added to the catalyst components.

The preparation method of the early carrier catalyst is usually to co-grind the magnesium compound and the titanium halide, or to grind the magnesium compound and then treat it with the titanium halide. However, the shape of catalyst particles obtained in this way is not good and the particle size distribution is very wide, which brings many difficulties to the production of polyolefin equipment.

Subsequently, many patents announced that various chemical reactions were used to prepare high-efficiency catalysts, and to a certain extent, the particle shape, catalyst efficiency and orientation ability of the obtained polymers were improved, and they have been applied in polyolefin industrial production. However, the particle size of the polymer obtained by this type of catalyst is small (<1mm), and it is not spherical. Representative patents of this type of catalyst include U.S.4952649 (Mitsui Petrochemical Company of Japan), U.S.4784983 (Beijing Research Institute of Chemical Industry, China) and the like.

Just have patent US4111835 (Italian Monte Edison Company) to announce the carrier that makes magnesium chloride alcoholate with spray method in the middle of the seventies, prepare spherical polyolefin catalyst with this carrier subsequently, but the yield of qualified carrier produced by spray method is lower, and Both catalyst efficiency and orientation ability were poor. Subsequently, in another patent of the company, US4399054, magnesium chloride alcoholate melt was sprayed at high pressure or stirred at high speed to disperse in a dispersion medium, and then shaped in a cold bath to prepare a spherical catalyst. However, the catalyst obtained by this method has poor catalyst efficiency and orientation ability, and the particle size of the polymer is less than 1mm, which is far from the size of the granulated material. The recently disclosed patent application publication specification of CN1047302A (Hymont Corporation of the United States) proposes a method for preparing a spherical carrier catalyst of a spherical polymer with a particle diameter of 1-5 mm. Catalyst efficiency and orientation ability are greatly improved compared to previous patents. However, the preparation process of this method is relatively complicated. When preparing a spherical carrier, the raw material MgCl ₂ ·C ₂ H ₅ OH=1:3.5 (molar ratio), after the reaction, MgCl ₂ ·nC ₂ H ₅ OH magnesium chloride alcoholate is obtained, and its n value is 3, and then heated to 180°C in a nitrogen stream to dealcoholize, so that the n value fell below 1.7, and then use the dealcoholized spherical carrier to synthesize the catalyst. On the one hand, such a dealcoholization device is required, the process is lengthened, and at the same time, more alcohol compounds are consumed, and the loss of nitrogen and heat energy is increased. In addition in the process of synthesizing the catalyst, use a large amount of TiCl ₄ (the molar ratio of Ti/Mg 1: 80), promptly produce 1Kg catalyst and will consume the titanium tetrachloride more than 100Kg, this will not only increase cost, and will cause more pollution. The catalyst obtained in this patent has the following characteristics: the specific surface area is 20～250m ² /g, and the X-ray spectrum of the catalyst has two situations: (1) there is reflection at 2θ as 15° angle and 2θ as 14.95° angle, or ( 2) There is no longer reflection at 2Θ of 35°, but is replaced by a "halo" of maximum intensity occurring between 2Θ of 33.5° and 35° of the halogen, and no reflection at 2Θ of 14.95°.

The purpose of the present invention is to overcome some deficiencies of the prior art, and adopt a simpler and more practical preparation method to obtain spherical catalyst components and spherical catalysts that can be used for olefin polymerization, and have their own characteristics in their structure and performance , it is suitable for the homopolymerization or copolymerization of olefins such as propylene, ethylene, 1-butene, etc. It has a high catalyst efficiency and a long life of the active center. The polymer is spherical in shape, with a particle size between 1 and 5mm, good fluidity and high apparent density, which provides conditions for omitting the granulation process in future production.

The present invention is described in detail as follows:

A spherical catalyst component for α-olefin polymerization, which is loaded on a spherical carrier of magnesium chloride alcoholate by halotitanium compound, characterized in that:

The spherical carrier is an alcoholate formed by a low-carbon alcohol equal to or less than four carbon atoms and anhydrous magnesium chloride, and dispersed in a dispersion medium composed of mineral oil and organic silicon compound that are incompatible with the alcoholate , relying on mechanical force to disperse into spherical particles with a diameter of 10-300 μm, wherein the molar ratio of magnesium chloride to low-carbon alcohol is 1:2-1:3;

The spherical carrier firstly reacts with titanium halide, is treated with an electron donor, and is washed with an inert solvent to obtain a spherical catalyst.

The preparation method of the spherical catalyst component used for the above-mentioned olefin polymerization is:

1. Preparation of Spherical Carriers

The preparation of the spherical carrier is to react anhydrous magnesium chloride and alcohol according to a certain ratio of heating to form a magnesium chloride alcoholate melt, stir and disperse at a high speed in a dispersant, and then rapidly cool to form microspherical solid particles of magnesium chloride alcoholate, after washing , and obtain a spherical carrier after drying.

Alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol and other high-carbon fatty alcohol compounds, among which ethanol is the best.

The molar ratio of alcohol to magnesium compound can be from 2.0 to 6.0, and the molar ratio of ethanol to magnesium chloride in the present invention is preferably 2.0 to 3.0.

The temperature range of alcohol and magnesium chloride to generate magnesium chloride alcoholate melt is different according to different types of alcohol and different magnesium alcohol molar ratios. Under the conditions of the present invention, the temperature of ethanol and magnesium chloride alcoholate melt is in the range of 90 to 140 ° C. , which is preferably 115-130°C.

The dispersant system uses hydrocarbon inert solvents, such as kerosene, paraffin oil, vaseline oil, white oil, etc., and also adds some surfactants or organic silicon compounds. The present invention adopts white oil and silicone oil as the dispersant system.

The magnesium chloride alcoholate melt is dispersed in the dispersant system of white oil and silicone oil to form an emulsion through high-speed stirring, and then it is discharged into the cooling liquid to cool and set rapidly to form magnesium chloride alcoholate microspheres.

Coolant uses inert hydrocarbons with lower boiling points, such as petroleum ether, raffinate, pentane, hexane, heptane, etc.

The obtained magnesium chloride alcoholate microspheres can be used as spherical carriers for synthesizing catalysts after being washed and dried. The molar ratio of the alcohol in the carrier to the magnesium compound (the n value of MgCl ₂ ·nROH) is between 2.0 and 3.0, preferably 2.0 to 2.5. The particle size distribution of the carrier is between 10 microns and 300 microns, preferably between 30 microns and 150 microns. The present invention prepares magnesium chloride alcoholate spherical carrier with an n value between 2.0 and 2.5, which can be directly used for synthesizing catalysts without going through the dealcoholization process, thereby reducing the consumption of alcohol and saving the equipment and equipment of the dealcoholization process. Energy consumption of nitrogen for the dealcoholization process.

2. Synthesis of Spherical Catalyst Components

The magnesium chloride alcoholate spherical carrier prepared above is used to treat with excess titanium tetrachloride, the treatment temperature is low at the beginning, and then the temperature is gradually increased. The inert solvent can be used as the reaction medium during the treatment, and titanium tetrachloride itself can also be used as the reaction medium. During or after the treatment process, some electron donors can be added to treat the carrier together with titanium tetrachloride, or after titanium tetrachloride is treated, the electron donors can be used to treat separately, so that the obtained catalyst contains A certain amount of electron donor, so that the obtained catalyst can have better orientation ability when used in olefin polymerization. After the treatment, it is washed with an inert solvent for several times, and the spherical catalyst component in the form of solid powder is obtained after drying.

Titanium tetrachloride treatment of the carrier can be done once or multiple times, generally twice or more is better.

The molar ratio of the total amount of titanium tetrachloride to the magnesium chloride in the carrier can be in the range of 20-200, preferably 30-60.

The initial treatment temperature can be in the range of -30°C to 0°C, preferably -20°C to -25°C. The final treatment temperature can range from 80°C to 136°C, preferably 100°C to 130°C.

The treatment reaction medium can be hydrocarbon compounds such as heptane, octane, toluene, xylene or raffinate oil with a boiling range above 80°C, gasoline, kerosene, etc. The electron donors are mainly aromatic carboxylic acid ester compounds, especially polybasic aromatic carboxylic acid esters, among which diisobutyl phthalate (DIBP) and di-n-butyl phthalate (DNBP) are preferred.

The washing solvent adopts low boiling point hydrocarbons, such as industrial hexane, petroleum ether, etc.

The spherical catalyst component obtained by the invention has the following characteristics: titanium content 1.5-3.0%, ester content 6.0-20.0%, chlorine content 52-60%, magnesium content 10-20%, inert solvent content 1-6%. The specific surface area of the catalyst is greater than 250m ² /g. In the X-ray spectrum of the catalyst, a diffraction peak appears at an angle of 15° at 2θ, and no diffraction peak appears at 35° at 2θ, but a "halo" (halo) of maximum intensity appears within the range of 28° to 36°.

The spherical catalyst component obtained in the invention is suitable for homopolymerization or copolymerization of ethylene, propylene and 1-butene.

In order to further illustrate the characteristics of the present invention, examples are given below.

Example 1

(1) Preparation of carrier

In the 250ml glass reactor that is equipped with reflux condenser, mechanical stirrer and thermometer, after fully replacing with nitrogen, add dehydrated alcohol 36.5ml, anhydrous magnesium chloride 21.3g (the mol ratio of dehydrated alcohol and anhydrous magnesium chloride is 2.8 : 1), heat up under stirring, add 75ml of white oil and 75ml of silicone oil after the magnesium chloride is completely dissolved, and keep the temperature at 120°C for a certain period of time. In another reaction bottle with a volume of 500ml and a high-speed stirrer, add 112.5ml of white oil and the same volume of silicone oil in advance, preheat to 120°C, and quickly press the previously prepared mixture into the second reactor to maintain At 120°C, stir at a high speed of 3500rpm for three minutes. Under stirring, transfer the material to the third reactor that has been added with 1600ml of hexane and cooled to -25°C until the transfer of the material is completed. The final temperature does not exceed 0°C. Filter, wash with hexane, wash away the silicone oil and white oil, and dry in vacuum to obtain 41g of spherical particulate magnesium chloride alcoholate. After sieving, take a 100-400 mesh carrier, and analyze and test the composition of the carrier as MgCl ₂ 2.38C ₂ H ₅ Oh.

(2) Catalyst synthesis

Take 7g of the above-mentioned MgCl ₂ ·2.38C ₂ H _5OH spherical carrier and slowly add it into a reaction bottle containing 150ml of titanium tetrachloride and pre-cooled to -20°C, gradually raise the temperature to 40°C, and then add diisophthalic acid Butyl ester (DIBP) 1.4ml, continue to heat up to 130°C, maintain for 2 hours, filter with suction, then add 120ml of TiCl ₄ , gradually heat up to 130°C, maintain for 2 hours, wash with 60ml of hexane for several times, until no chlorine appears in the filtrate The resulting filter cake was vacuum-dried.

The characteristics of the catalyst were measured as follows: the Ti content was 2.2%, the DIBP content was 11.2%, and the specific surface area was 314 m ² /g. The X-ray spectrum has a diffraction peak at 2θ of 15°, and no diffraction peak at 2θ of 35°, but is replaced by a "halo" of maximum intensity at an angle of 28° to 36°.

(3) Propylene polymerization

In a polymerization kettle equipped with a stirring and temperature regulating device fully replaced by propylene, add 0.5mmol/ml triethylaluminum hexane solution 3ml, 0.1mmol/ml diphenyldimethoxysilane hexane solution at room temperature 1ml, 15mg of the above-mentioned catalyst was added, 2.5l of liquid propylene and 400Nml of hydrogen were added under stirring, the temperature was raised to 70°C and maintained for 2 hours to obtain 665g of polymer.

Test polymer: polymer melt index M11.44g/10 minutes, polymer congruence TII is 98.5%, polymer apparent density BD is 0.47g/ml, polymer particle size is 1-5mm ball , the catalyst efficiency is 38.0Kg polymer/g catalyst (the results are shown in Table 1).

Example 2

(1) carrier preparation

Except that the addition of absolute ethanol was 37.8ml, the rest were prepared in the same way as in Example 1 to obtain 42g of spherical particulate magnesium chloride alcoholate carrier, which was analyzed to be MgCl ₂ ·2.48C ₂ H ₅ OH.

(2) Catalyst synthesis

Get above-mentioned MgCl ₂ 2.48C ₂ H ₅ OH spherical carrier 7g, according to the same method of embodiment 1, adopt twice to add TiCl _The amount is 100ml, the catalyst characteristics obtained are as follows: Ti content is 2.43%, DIBP content is 12.2%, and the specific surface area is 428m ² /g. The X-ray spectrum has a diffraction peak at 2θ of 15°, and no diffraction peak at 2θ of 35°, but is replaced by a "halo" of maximum intensity at an angle of 28° to 36°.

(3) Propylene polymerization

Propylene polymerization was carried out in the same manner as in Example 1, and the results are listed in Table 1.

Example 3

(1) carrier preparation

The preparation of the support was the same as that in Example 1, except that vacuum drying was carried out at 70° C. to obtain a support composition of MgCl ₂ ·2.03C ₂ H ₅ OH.

(2) Catalyst synthesis

Adopt the method identical with example 2, obtain catalyst characteristic as follows: Ti content is 2.05%, DIBP content is 9.04%, and specific surface area is 277m ² /g, and X-ray spectrum is that 15 ° angle appears diffraction peak at 2θ, and 2θ is 35 There is no diffraction peak at the angle of °, but it is replaced by the "halo" of the maximum intensity at the angle of 28° to 36°.

(3) Propylene polymerization

Propylene polymerization was carried out in the same manner as in Example 1, and the results are listed in Table 1.

Example 4

(1) carrier preparation

Same as Example 1.

(2) Catalyst synthesis

Take 7g of the carrier obtained in Example 1, slowly add 100ml of titanium tetrachloride, 80ml of heptane and pre-cooled to -30°C reaction flask, gradually raise the temperature to 40°C, and then add diisobutyl phthalate 1.4 ml, continue to heat up to 100°C, maintain for 2 hours, add 120ml of TiCl ₄ after filtration, gradually raise the temperature to 130°C, maintain for 2 hours, wash and dry as in Example 1.

The characteristics of the obtained catalyst are as follows: the Ti content is 1.96%, the DIBP content is 10.4%, and the specific surface area is 316 m ² /g. The X-ray spectrum has a diffraction peak at an angle of 2θ of 15°, and no diffraction peak appears at an angle of 2θ of 35°, but is replaced by a "halo" of maximum intensity that appears within the range of 28° to 36°.

(3) Propylene polymerization

Propylene polymerization was carried out in the same manner as in Example 1, and the results are listed in Table 1.

Example 5

(1) carrier preparation

Same as Example 1.

(2) Catalyst synthesis

Except that 80ml of heptane was changed into 80ml of toluene, and 1.4ml of diisobutyl phthalate was changed into di-n-butyl phthalate, all the other operations were the same as in Example 4.

The characteristics of the obtained catalyst are as follows: the Ti content is 2.34%, the DNBP content is 11.5%, and the specific surface area is 323 m ² /g. The X-ray spectrum has a diffraction peak at a 2θ angle of 15°, and there is no diffraction peak at a 2θ angle of 35°, but is replaced by a "halo" of maximum intensity that appears within the angle range of 28° to 36°.

(3) Propylene polymerization

Propylene polymerization was carried out in the same manner as in Example 1, and the results are listed in Table 1.

Example 6

The carrier preparation and catalyst synthesis were the same as in Example 2, and the catalyst in Example 2 was used for propylene-ethylene block copolymerization. Carry out propylene polymerization according to the method of embodiment 1 first, the polymerization temperature is 70 ℃, release the unpolymerized propylene in the reactor after maintaining for 2 hours, then feed the mixed gas with ethylene/propylene molar ratio of 2, keep the pressure of the kettle at 0.5MPa, React at 75° C. for 1 hour to obtain 635 g of propylene-ethylene block copolymer. The catalyst efficiency is 4.54 Kg polymer/g catalyst. After analysis, the ethylene content in the polymer is 10.4%. The other results are shown in Table 1.

Table 1 serial number Catalyst efficiency KgPP/g.cat Polymer MIg/10min Polymer TII% Polymer BDg/ml Polymer Appearance Example 1 38.0 1.44 98.5 0.47 1-5mm ball Example 2 37.0 1.75 98.3 0.46 1-5mm ball Example 3 35.4 1.66 98.2 0.48 1-5mm ball Example 4 31.5 1.53 98.0 0.47 1-5mm ball Example 5 30.5 2.12 97.5 0.46 1-5mm ball Example 6 45.4 1.70 / 0.45 1-5mm ball

Claims (10)

1, a kind of spherical catalyst component of used in alpha-olefines polymerization, it is that the halogen titanium compound is carried on the ball type carrier of magnesium chloride alcohol adduct, it is characterized in that:

Described ball type carrier is to be equal to or less than the low-carbon alcohol of four carbon atom and the alcohol adduct that Magnesium Chloride Anhydrous forms, be dispersed in the dispersion medium of forming with immiscible mineral oil of this alcohol adduct and silicoorganic compound, rely on the strength of machinery to make it be dispersed into the spheroidal particle that diameter is 10～300 μ m, wherein the mol ratio of magnesium chloride and low-carbon alcohol is 1: 2～1: 3;

This ball type carrier reacts with halogenated titanium earlier, handles with electron donor again, obtains the spherical catalyst component after the inert solvent washing.

2, spherical catalyst component according to claim 1 is characterized in that, in the described ball type carrier, the mol ratio of magnesium chloride and low-carbon alcohol is 1: 2～1: 2.5.

3, spherical catalyst component according to claim 1 is characterized in that, described low-carbon alcohol is methyl alcohol, ethanol, n-propyl alcohol, Virahol, propyl carbinol or isopropylcarbinol.

4, spherical catalyst component according to claim 1 is characterized in that, described electron donor adopts diisobutyl phthalate or n-butyl phthalate.

5, spherical catalyst component according to claim 1 is characterized in that, described mineral oil adopts kerosene, paraffin oil, vaseline oil or white oil.

6, spherical catalyst component according to claim 1 is characterized in that, described silicoorganic compound are silicone oil.

7, a kind of method for preparing the described spherical catalyst component of claim 1 comprises the steps:

The preparation of ball type carrier: with Magnesium Chloride Anhydrous and low-carbon alcohol is to mix in 1: 2～1: 3 in molar ratio, temperature reaction generates magnesium chloride alcohol adduct melt, temperature of reaction is 90～140 ℃, after dispersion medium high speed dispersed with stirring, be discharged into the microspheroidal solid particulate that the cooling fluid quick cooling forms the magnesium chloride alcohol adduct, after washing, drying, obtain ball type carrier;

With excessive halogenated titanium above-mentioned prepared ball type carrier is handled at least once, treatment temp begins to be-30 ℃～0 ℃, progressively be warming up to 80～130 ℃ then, can be during processing with inert solvent as reaction medium, also can in treating processes, can add electron donor and handle carrier with halogenated titanium itself as reaction medium with halogenated titanium, also can be after halogenated titanium be handled, use the electron donor individual curing again, after the inert solvent washing, obtain the spherical catalyst component.

8, the preparation method of spherical catalyst component according to claim 7 is characterized in that, described cooling fluid is selected from pentane, hexane, heptane, sherwood oil, raffinates oil.

9, the purposes of the described spherical catalyst component of claim 1 is characterized in that being suitable for the equal polymerization or the copolymerization of ethene, propylene, 1-butylene.

10, a kind of spherical catalyst is characterized in that, comprises following component:

(1) spherical catalyst component, it is that titanium tetrachloride is carried on the ball type carrier of magnesium chloride alcohol adduct, wherein said ball type carrier is the alcohol adduct that ethanol and Magnesium Chloride Anhydrous form, be dispersed in the dispersion medium of white oil and silicone oil composition, rely on the strength of machinery to make it be dispersed into spheroidal particle, wherein the mol ratio of magnesium chloride and low-carbon alcohol is 2.38 or 2.48 or 2.03; This ball type carrier elder generation and titanium tetrachloride reaction are handled with diisobutyl phthalate again, obtain the spherical catalyst component after the inert solvent washing;

(2) triethyl aluminum;

(3) dimethoxydiphenylsilane.